Improvement in wood-pulping machines



I-IVOELTER.

WOOD PULPING MACHINE.

1096,515. l Patented 1\Imf.2, 1869.I

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vLetters Patent No. 96,515, dated November 2, 186).

IMPROVEMENIIN WOOD-PULPING- MACHINES.

The Schedule referred to in these Letters Patent and makingpart of the same.

To all whom 'it may concern:

.Be it known that I, HEINRICH VOELTER, of Heidenheim, in the Kingdom of Wurtemberg, havel invented a new and usefiil` Improvement in Vood-Pulping Machines; and I do hereby declare the following to be a full, clear, and exact description thereof, which will enable those skilled in the art to make and use the same, reference being had to the accompanyingdrawing, forming part of' this specification, in which drawing- 4 Figure l represents a plan or top view of' this in- Vention.

Figure 2 is a transverse section of the same.

Figure 3 is a plan of a modification ofthe saine.

Figure 4 is asimilar view of the saine in a larger scale than the previous figure.

Similar letters indicate corresponding parts.

This invention relates to' an improvement in that part of' a wood-pulping machine, which serves to assort the fibres after the wood has been reduced by grinding-mechanism, such, for instance, as that described in Let-ters Patent granted to me in the United States, on the 10th of' August, 1858, and also on the 22d of' May, 1866.

In these patents I have described assorting-cylinders or drums, which are intended to assort the fibres according to their different degree of fineness, and these drums have heretofore been covered with wire netting or gauze, having square meshesj But long experience has shown to me that the value of the pulp produced would be greatly enhanced if' the length of the line fibres could be increased, while in the present inode of assorting the fibres, the long,f1ne fibres could be obtained only mixed with the coarse fibres.

The reason why it was not possible to separate the long, fine libres from the coarse fibres, I found in the construction of' the asserting-sieves, the meshes of' which have heretofore always been square, and since these meshes had to be very nc, in order to prevent the passage of' coarse fibres through them, it is obvious, that with the fineness of the sieves, the

length of the fibres, capable of passing throughthem,

was necessarily reduced in the same proportion'. The fille, long fibres therefore remained mixed with the coarse fibres, and, in consequence thereof, their value was greatly depreciated, or, if' they were returned Ato the reducing-machine, their length was reduced below the required point.

This 'difficulty I have avoided simply by using sieves A with oblong meshes, as shown in the drawing.

If the fineness of theseI wires is increased, the meshes still remain long enough to allow the passage through them of the long, fine fibres, while the coarse fibres are prevented from passing, and the value'of' the pulp produced is materially improved.

In constructing my improved sieve with oblong openings, several difficulties had to be overcome, since the meshes being choked up by coarse fibres at short intervals, have to be cleaned repeatedly, and in being cleaned they are subjected to a considerable strain,

which is liable to disturb the shape of the meshes.

I have, therefore, constructed `the sieves of wires of' different' thickness and elasticity, as shown inv figs. l and 2, where fine and elastic wires are used in pairs as filling, with coarser wire forming the warp, said fine wires being placed close together and twisted in opposite directions round the coarse wires, as shown. Instead of' using fine wires in pairs, as shown in figs. l and 2, I have also used, for the filling, strands of' wire produced by twisting a number of such fine wires together, as shown in figs. 3 and 4. Such strands preserve a certain degree of elasticity, and when thrown into the warp, they are capable of retaining the'warpthreads in position, and thereby the dislocation of the meshes by the frequent operation of cleaning is obviated.

That I claim as new, and desire to secure by Letters Patent, is

In wood-pulping machines, the use of' assortingsieves withoblong meshes, constructed as herein shown and described.

This specification August, 1869.

signed lby me,this 21st day 0i' 'unina vonUrEn.

Witnesses:

GUsTAv SCHON, ROBERT GU'roKUNsT. 

